I can see myself making use of the online tool stich.it. It could, for example, be a convenient way to show which items in a gallery are my favourites. I tested it on a gallery of Discworld-inspired lego constructions that a friend pointed out on Twitter.

Amazing site for tracking the current location of aeroplanes. Via TYWKIWDBI, which also links to site for ships, although the interface for that is not as stunning.